AP PHYSICS MIDTERM-EMERGENCY .please help

1. The problem statement, all variables and given/known data
We are given an Atwoods machine with two known masses on either side. On one of the masses two objects of unknown mass are added. We have to perform measurements to determine the resulting acceleration. Then from the accelerations we have to calc. the mass of each oth the unknown objects to the nearest .01 kg. we are not given the masses of the two known objects YET..so can we just call them a and b.

2. Relevant equations

F=ma
Fmg=9.8
mg-t=ma

3. The attempt at a solution

i have no idea of even to start it except that maybe we use mg-t=ma and go from there????
then would i consider t-mg=ma and have m(1)a(1)=m(2)a(2)
would anyone know how to do this
the link to the actual website where the ? is posted is